Period of Rotation of the Sun

"The sunspots are found to move across the disc from day-to-day; from this it is inferred that the Sun rotates with a period of about 25 days at its equator."

25 days

"Sun." The Columbia Encyclopedia, Sixth Edition. 2008.

"Observations of sunspots and studies of the solar spectrum indicate that the sun rotates on its axis from east to west; because of its gaseous nature its rate of rotation varies somewhat with latitude, the speed being greatest (a period of almost 25 days) in the equatorial region and least at the poles (a period of almost 35 days."

25-35 days

Stallo Bernhard, John. The Concepts and Theories of Modern Physics. New York: Adamant, 2000.

"We are able to test this question mathematically, by calculating from the sun's actual period of rotation, which is twenty-five and three tenths days, what would be the velocity of rotation if, conserving the sum of the areas described by all its material points, it were expanded so that its radius, which is now equal to one hundred and twelve times the equatorial radius of the earth, became equal to the distance from the earth to the sun, or from Neptune to the sun."

"The Sun's period of rotation at the surface varies from approximately 25 days at the equator to 36 days at the poles. Deep down, below the convective zone, everything appears to rotate with a period of 27 days."

25-36 days

The period of rotation of the sun is determined by use of sunspots. Sunspots
which are cyclonic disturbances in the photosphere of the sun are found to
move across the solar disk from day to day.They differ widely in duration,
sometimes lasting for several months and sometimes disappearing in the course
of a few hours. The plane of rotation of these sunspots are inclined seven
degrees to the ecliptic. The motion of sunspots determine the rate of rotation
at a particular latitude. The sun doesn't rotate as a solid body, but rather
varies its rotation period from the equator to the poles. The various rotation
periods may also vary with time. Sunspots move by small amounts over the surface
of the sun, but these movements are small enough that they may be ignored and
therefore sunspots may be used to determine the rotation of the sun.

The sun rotates on its axis from east to west. The sun as a whole has no single
period of rotation, but different portions of its surface perform their revolutions
in different times. The equatorial regions move more rapidly than the rest of
the solar surface, and as a result they also complete the entire rotation in
shorter time. The period of rotation of the sun varies somewhat with latitude,
(at higher latitudes the sun tends to rotate more slowly), but it is estimated
that the sun's period of rotation at the surface varies from about 25 days
at the equator to about 35 days at the poles.

Chelsea Edobor -- 2008

Bibliographic Entry

Result(w/surrounding text)

StandardizedResult

Ebbinghausen, E. G. Astronomy. 5th ed. Merrill, 1985.

"The sun's roational period is about 25 days at the equator,27 days at 35 degrees latitude,33 days at 75 degrees latitude, and about 35 days near the poles."

The movement of solar surface features (sunspots) show that
the sun is in rotation about its axis. Observations also reveal
that the sun's equator is inclined about seven degrees to the
plane of the ecliptic. The sun rotates from west to east in the
same direction as the earth. However unlike the earth, the sun
does not rotate as a solid body.

The motion of sunspots determine the rate of rotation at a
particular latitude. Sunspots are fairly circular structures that
contain two well-defined parts. The spots occur in pairs or in
groups, however with two main spots. The line that joins the centers
of a pair is almost parallel to the sun's equator. At the equator
the sun's rotational period is twenty-five days while at higher
latitudes the sun tends to rotate more slowly. The rotational
period near the poles it is thirty-five days. In contrast to the
earth, the position of a place on the sun changes as the places
closer to the equator speed ahead. The surface of the sun is not
solid but fluid.